This study aimed to find out whether annual Faecal Immunochemical Tests (FIT) for colorectal cancer are accurate enough to replace three-yearly colonoscopy in people who have previously had a polyp or polyps removed at colonoscopy and deemed to be at ‘intermediate risk’ of colorectal cancer according to the 2002 national post-polypectomy surveillance guidelines. FITs are quicker, cheaper and easier than colonoscopy, which has risks of complications.
Scientific evidence for use of FIT for post-polypectomy surveillance of intermediate-risk patients to reduce costs to NHS
Overall, the study has so far demonstrated that annual FIT could identify 59 to 72 of every 100 cancers and 34 to 57 of every 100 patients with advanced adenomas if repeated annually over three years. We found that replacing three-yearly colonoscopy surveillance in intermediate-risk patients with annual FIT could reduce colonoscopies by 71% and significantly cut costs to the NHS, but certain cancers and adenomas could be missed.
We also carried out analyses to determine how cost effective an annual FIT was compared to three yearly colonoscopies and to investigate patients’ surveillance preferences. Annual FITs were considerably cheaper than three-year colonoscopy. Patients reported that the FIT was easy to use and provided reassurance. However, some were concerned that the FIT would not be as effective as colonoscopy.
To our knowledge, this study is the only one to have evaluated FIT for monitoring people who have previously had a large polyp, or a few small polyps, removed at colonoscopy. In our most recent 2024 analysis, no change in results across three annual FITs was associated with a low advanced colorectal neoplasia (ACN) detection rate, while a serial increase in FIT values was associated with higher ACN detection rates. Further research should consider if sequential rounds of FIT could be used for stratifying individual risk.
Continued research will help to define a clear role of FITs in surveillance.